A trend in modern dairies is to rely upon robotic or automated milking systems because these milking robots can significantly reduce labor costs and demands in milk harvest. One reason frequently given for considering an automated milking system (AMS) is a reduction in the labor force necessary for the farm. Another reason sometimes given is that a smaller farm can consider expansion of cow numbers without a large change in its labor force. The reason for the labor savings is that most milking cows of the dairy herd will visit the robot milking machines voluntarily and that the robot will, without manual assistance, milk the visiting cow. The milking occurs throughout the day and is enabled by the cows' unobstructed access to the robots.
By contrast, in most dairy farms exploiting a conventional milking parlor configuration, laborers will take advantage of the scheduled movement of the herd through the parlor in order to scrape alleys, dress stalls and maybe even put down fresh feed. While the cows are out of the way, it is easy to run a skid steer loader and dress the empty stalls. But, this method of cleaning the area around the robots will not be available in AMS barns both, because the presence of the skid steer loader will discourage cows seeking access to the robot, and because the herd is never in a single location, such as in the free-stalls leaving the robot milking parlor. The two methods of operation are not consistent, with the same methods of hygiene for the herd and barn. Movement of cows follow distinct patterns in each of the two types of barns, i.e. AMS and conventional herringbone milking parlors. Specifically, cows want to go to be milked, in an AMS barn, whenever they want. Obstructing their progress towards the robots will cause cows to yield less milk with real economic impact on the dairy.
Just as economic factors drive dairymen to consider a conversion to AMS, economic factors also drive barn design changes to afford lactating cows unfettered access to the robots. By conventional design, the principal driver is the placement of gutters and floors necessary to optimally clean the barn. This tends to place the milking parlor as far from the free stalls as possible to allow cleaning in shifts, i.e. when the cows are being milked, the stalls and alleys are cleaned. When the cows are in the stalls, the parlor is cleaned. Redesigning the barn to accommodate AMS generally means placing the robots and the floor area immediately proximate to the robots as well as a the staging or holding area by which cows approach the robots (together referred to as the “robotic milking parlor” herein) in a central location in the barn. Thus, cows can reach the robots through various and convenient paths from their free-stalls.
In AMS barns, however, that the robotic milking parlor is centrally located means that it bears the greatest volume of traffic within the barn. In contrast to the alleys and lanes proximate to the stalls or cubicles, the traffic in the robotic milking parlor is concentrated along the track to and from the robots and is exposed to more manure. Even, when compared to a conventional dairy barn, the robotic parlor bears more traffic than a conventional herringbone parlor. The average AMS milking frequency is 2.8 times a day, with a range of 2.4 to 3.2, in contrast to the twice-daily milkings common in a conventional dairy.
To clean this highly trafficked area, the conventional methods have been to scrape the flooring decking between each milking, to flush the decking with water from a hose, or a combination of scraping and flushing. In many barns, this simply means moving some of the labor from milking to cleaning. Less labor than the several persons used for conventional milking, but constant labor given cow-initiated milking. One solution has been to automatically flush the robot area with a large volume of water twice a day. Unfortunately, this has proven largely impractical.
AMS barns using conventional flush techniques do not prevent the cows from visiting the milking robots as cows are willing to walk through a volume of water consistent with flushing by conventional methods. However, a volume sufficient to entrain trod-in and dried manure is also enough to wet hooves and to splash onto teats. Pooling on the floor in the robotic milking parlor presents a significant risk of either foot rot or mastitis. (Mastitis is an inflammation of the mammary gland or udder. Mastitis in dairy cows is caused by udder infections, usually resulting from bacteria introduced either during the milking process or from environmental contact. Examples include contamination from milking equipment, milking personnel, manure contamination or dirty stalls.) With greater traffic, the volume of deposited contamination including contamination by dirt and manure is necessarily greater as well. But the greater volume of water used means a greater risk of disease.
Maintaining the cleanliness of the floor area within the robotic milking parlor without the risk of disease becomes an important objective and, in AMS dairies, is conventionally met by providing a laborer to either scrape or to hose flush this parlor area frequently during periods when the robots are in use. And as stated above, this must be performed continuously, as restricting the cows' access to the robots, any more than is necessary, adversely impacts either of harvested milk volumes or of health of the herd. For that reason, conventional means of keeping the robotic milking parlor optimally clean also means employing such additional help as is necessary to scrape or hose down the periphery of the robotic milking parlor.
Battle lines in the debate over cleaning dairy barns continues to rage over the relative advantages of scrape and of flush cleaning. Cows have proven themselves tolerant of alley scrapers and of flush techniques so long as there is an alternate path to or from their stalls. But since the free-stall area of a robotic barn is never free from cows, cleaning with a tractor or skid steer is not recommended as it either distresses the cows or interferes with their access to the robot. And, the layout of many robotic barns makes it difficult to clean the barn using traditional cable drawn alley scrapers, because barn layouts make use of large open areas in the robotic milking parlor and often have larger cross-overs than in parlor barns.
Recognizing the issues presented by the area around the robots in an AMS barn, dairymen have attempted to adapt several convention means of cleaning which fall into four categories:                scrape (mechanical);        slatted floor manure systems;        flush (hydraulic); or        a scrape-flush combination.        
Scrape or mechanical collection involves the removal of the manure from the robotic milking parlor by manual or mechanic movement of a blade over the surface. Scraping requires using some pushing means. Mechanical scrapers have the advantage of providing automatic mechanized rapid removal of manure. Mechanical scraping is the cheapest method and is the only option for nonconcrete surfaces. In the context of a robotic milking system, the preferred method is by a blade or a scrape driven by a pulley system. While such systems interfere with cows access to the milking robots, the interference is less than by skid steer scraping.
Slatted-floor barns originally were designed with narrow alleyways that concentrated cow traffic to push the manure through the slats. As interest in cow comfort increased and lying times in stalls lengthened, reduced cow movement in the alleys resulted in a greater build-up of manure in the alleyways. The most effective way to deal with this manure build-up is to use some form of scraper to push the manure down through the slats.
In conjunction with slatted-floor barns, scrapers drawn by a cable or a pushed by a shuttle drive are the most popular. These scrapers do not have to be as rugged as regular alley scrapers since they do not drag manure down the barn alley, but rather push the manure through the slats. Automatic scrapers are effective in pushing manure through slats, but they still involve cables or shuttle arms that have to be maintained as well as corner wheels or other drive mechanisms that have to be installed outside the cow area so as not to be a hazard to cow traffic, adding to the size of the barn.
Flush, or hydraulic, manure collection exploits a flow of water to entrain and convey manure and dirt out of the robotic milking parlor. Such a flow comes, in a conventional dairy barn, through hoses manually directed, urging manure into gutters to be conveyed to manure storage lagoons. As in any dairy, water plays a crucial role in the cleaning of both the milking robots and the stalls and alleys. Water transports heat energy and cleaning chemicals used in robotic machine cleaning; water volume and flow rate creates turbulence—a “scrubbing” action or lifting force; water carries away milk residue, yard debris, and, especially, manure.
Conventional flush systems require a large volume of water to clean properly. Most systems use some form of solid-liquid separation to reclaim water, then recycle the separated liquids to be used as flush water. The cleaner the flush water is, the better the job it will do in cleaning the floors. If there is too much manure left in the flush water, a scum will build up on the floors over time, making them quite slippery. More cleaning means less disease, fewer cleanings may conserve water but they also result in higher bacteria counts meaning reduced milk quality. The conventional means of high volume flush cleaning has been set out above.
Importantly, with each of the methods set out above, the use of the method must not interfere with the cow's free use of the robots. Any such interference that might impede the free use of the robots, might also prevent the greater milk volume that adoption of robotic milking promises. What is needed in the art, therefore, is an automated means of removing manure from the heavily trafficked area proximate to the milking robots without requiring labor or allowing excessive water to contact hooves or teats.